/* scanlzma, scan for lzma compressed data in stdin and echo it to stdout. Copyright (C) 2006 Timo Lindfors This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. */ /* Usage example: $ wget http://www.wifi-shop.cz/Files/produkty/wa2204/wa2204av1.4.1.zip $ unzip wa2204av1.4.1.zip $ gcc scanlzma.c -o scanlzma -Wall $ ./scanlzma 0 < WA2204-FW1.4.1/linux-1.4.bin | lzma -c -d | strings | grep -i "copyright" UpdateDD version 2.5, Copyright (C) 2005 Philipp Benner. Copyright (C) 2005 Philipp Benner. Copyright (C) 2005 Philipp Benner. mawk 1.3%s%s %s, Copyright (C) Michael D. Brennan # Copyright (C) 1998, 1999, 2001 Henry Spencer. ... */ /* LZMA compressed file format */ /* --------------------------- */ /* Offset Size Description */ /* 0 1 Special LZMA properties for compressed data */ /* 1 4 Dictionary size (little endian) */ /* 5 8 Uncompressed size (little endian). -1 means unknown size */ /* 13 Compressed data */ #define BUFSIZE 4096 int find_lzma_header(unsigned char *buf) { return (buf[0] < 0xE1 && buf[0] == 0x5d && buf[4] < 0x20 && (memcmp (buf + 10 , "\x00\x00\x00", 3) == 0 || (memcmp (buf + 5, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 8) == 0))); } int main(int argc, char *argv[]) { char buf[BUFSIZE]; int ret, i, numlzma, blocks=0; if (argc != 2) { printf("usage: %s numlzma < infile | lzma -c -d > outfile\n" "where numlzma is index of lzma file to extract, starting from zero.\n", argv[0]); exit(1); } numlzma = atoi(argv[1]); for (;;) { /* Read data. */ ret = fread(buf, BUFSIZE, 1, stdin); if (ret != 1) break; /* Scan for signature. */ for (i = 0; i<BUFSIZE-23; i++) { if (find_lzma_header(buf+i) && numlzma-- <= 0) { fwrite(buf+i, (BUFSIZE-i), 1, stdout); for (;;) { int ch; ch = getchar(); if (ch == EOF) exit(0); putchar(ch); } } } blocks++; } return 1; }